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Old 02-15-2012, 01:39 PM   #1
dukes7779
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Jun 2011
, NY
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Recently made the switch from Brew Pal to iBrewmaster. I plugged the same recipe into both and got different ABVs. Brew pal said 7.4% and iBrewmaster said 6.8%. OG, FG, efficiency, etc. were all the same for each. What gives??



 
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Old 02-15-2012, 03:41 PM   #2
Lucky_Chicken
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Jul 2011
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Maybe different yeast package dates? if those systems have them. Beersmith changes fermentation based on yeast viability.



 
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Old 02-15-2012, 03:53 PM   #3
weirdboy
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OG and FG were exactly the same in each?
I would double check those numbers.


There are some more complex and less complex formulas for calculating ABV, but they shouldn't differ by that much I think.

 
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Old 02-15-2012, 04:11 PM   #4
rhamilton
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Sep 2011
Austin, Texas
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I can tell you from my personal brew software development -- those calculations are complicated and hairy at best in terms of calculating ABV based on yeast attenuation. And having a 1% difference between beer software is not unheard of.

For example - a 70% att. yeast shows a 7.9% ABV estimate, an 80% att. yeast will show 8.9% ABV

You'll have to check what attenuation the software is basing the calculations on and see of it matches your yeast strain. Sometimes yeast data is self reported and it can be unreliable.
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Old 02-15-2012, 05:10 PM   #5
weirdboy
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No check the OG and FG before you do anything else.


If the attenuation is different then the FG should be, too.




And attenuation comes from more than just the yeast strain. There is no software and no data out there that can accurately predict attenuation because it depends on stuff like the grain bill and mash temps in addition to the strain, fermentation profile, etc.



 
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